One of the vibrating screens on the crusher floor. Ore from the hopper and the primary crushers was segregated by size and mineral content using screens and picking belts. All plus 4-inch size ore went over two picking belts that carried it past groups of four men who raked off the mineralized rock. Plus 3-inch size went over similar picking belts. All minus 3-inch size ore and all mineralized ore raked off the picking belts was crushed to progressively finer sizes as it passed through gyratory crushers, cone crushers and two roll crushers. Fines were screened out at every stage and fed to the bal1 mills. The ultimate result was 3 products; (1 ) plus 4-inch waste, (2) plus 3-inch waste, and (3) minus 1 1/2-inch ball-mill feed.